This invention is concerned with a multi-function wrap useful as a structural element to prevent racking and jamb bowing of a window assembly and a door assembly during transport and installation and, after installation, as an integral vapor barrier and air infiltration seal. A common problem associated with premanufactured window assemblies and door assemblies is that during transport and installation the assemblies are susceptible to stresses which distort the frame of the assemblies such that the corners of the frame are not right angles. The term for this distortion is called "racking". This distortion of the frames may result in misalignment and binding of the window sashes or door in the frame during and after installation resulting in unsatisfactory operation of the window or door.
Acceptable limits on the magnitude of racking of a window frame as determined by the relative horizontal displacement of a head of the window frame with respect to a sill of the window frame on a typical vertical sash window 6 feet or more in height and 3 feet or less in height is 0.1 of an inch or less and 0.05 of an inch or less, respectively. Similarly, acceptable limits on the magnitude of racking of a door frame as determined by the relative horizontal displacement of a head of the door frame with respect to a sill of the door frame on a typical single prehung door frame 6 feet or more in height is 0.1 of an inch or less.
In the past, premanufactured window frames and door frames have been rigidified to prevent racking by the application of tight banding around the frame of the window assembly or door assembly or across the frame vertically and/or horizontally. The rigidifying systems were then removed from the window assembly or door assembly prior to or after installation of the window or door. After installation of the window or door the rigidifying systems serve no useful purpose and impede the operation of the window or door and therefore must be removed from the window assembly or door assembly and discarded. It will be appreciated that disposal of the rigidifying system by burning or dumping in a landfill further exemplifies the waste and inefficiency of the banding process. A representative rigidifying system employing banding is disclosed in U.S. Pat. No. 4,691,477.
Additional rigidifying systems for window assemblies have been known to employ shipping clips to retain pivot pins engaged and maintain the sash closed and in a non-racked position. However, the use of shipping clips and pivot pins suffer from the disadvantage that the pins are susceptible to being pulled out of the window when the window is turned on the side.
It will be appreciated from the foregoing that there is still a significant need for an improved rigidifying system to prevent racking of a window or prehung door during transport and installation that overcomes the problems of the prior art.
Accordingly, one aspect of the present invention is to provide a rigidifying system entailing a wrap useful as a structural element to prevent racking and jamb bowing of a premanufactured window or prehung door during transport and installation and, after installation, useful as an integral vapor barrier and air infiltration seal. Another aspect of the present invention is to provide a wrap that maintains a prehung door or window in a nonracked position during transport and installation and protects the finish or the window surfaces from incidental bumps and nicks. Another aspect of the present invention is to provide a wrap that may be easily converted to a vapor barrier and air infiltration seal upon installation of the window or door. Still another aspect of the present invention is to provide a wrap that is simple and economical to manufacture. A further aspect of the present invention is to provide a door frame assembly or window frame assembly that is protected from bumps and nicks that may occur in the transport and installation of prehung door assemblies or premanufactured window assemblies.